Rising BMI Has Slowed Improvement in U.S. Mortality

Last Updated: January 16, 2018.
The rate of improvement in mortality in the United States has been slowed by rising body mass index, according to a study published online Jan. 15 in the Proceedings of the National Academy of Sciences.

Increase in maximum lifetime BMI estimated to have cut life expectancy by 0.9 years at age 40 in 2011

TUESDAY, Jan. 16, 2018 (HealthDay News) -- The rate of improvement in mortality in the United States has been slowed by rising body mass index (BMI), according to a study published online Jan. 15 in the Proceedings of the National Academy of Sciences.

Samuel H. Preston, Ph.D., from the University of Pennsylvania in Philadelphia, and colleagues examined the extent to which rising BMI accounts for reductions in the rate of mortality using data from cohorts of the National Health and Nutrition Examination Survey and linked mortality files. Models comparing mortality trends in the presence and absence of adjustment for maximum lifetime BMI (Max BMI) were used to estimate the role of BMI.

The researchers found that addition of maximum BMI into a model controlling for age and sex increased the decline in the annual rate of mortality by 0.54 percent. The results persisted with inclusion of other variables, differences in the measurement of Max BMI, and trend evaluation methods. Relative to international mortality trends and to alternative mortality futures simulated by the Social Security Administration, the effect of rising Max BMI was large. Over the period 1988 to 2011, the increase in Max BMI was estimated to have reduced life expectancy at age 40 years by 0.9 years and to account for 186,000 excess deaths in 2011.

"Rising levels of BMI have prevented the United States from enjoying the full benefits of factors working to improve mortality," the authors write.